diff --git a/src/librustc/ich/impls_ty.rs b/src/librustc/ich/impls_ty.rs
index 4eb4f0edafe40..bb3051b546e64 100644
--- a/src/librustc/ich/impls_ty.rs
+++ b/src/librustc/ich/impls_ty.rs
@@ -886,9 +886,8 @@ for ty::TypeVariants<'gcx>
             TyGeneratorWitness(types) => {
                 types.hash_stable(hcx, hasher)
             }
-            TyTuple(inner_tys, from_diverging_type_var) => {
+            TyTuple(inner_tys) => {
                 inner_tys.hash_stable(hcx, hasher);
-                from_diverging_type_var.hash_stable(hcx, hasher);
             }
             TyProjection(ref projection_ty) => {
                 projection_ty.hash_stable(hcx, hasher);
diff --git a/src/librustc/infer/resolve.rs b/src/librustc/infer/resolve.rs
index 5e70c0ce368fc..77b722c5695f8 100644
--- a/src/librustc/infer/resolve.rs
+++ b/src/librustc/infer/resolve.rs
@@ -173,12 +173,6 @@ impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for FullTypeResolver<'a, 'gcx, 'tcx>
                 ty::TyInfer(_) => {
                     bug!("Unexpected type in full type resolver: {:?}", t);
                 }
-                ty::TyTuple(tys, true) => {
-                    // Un-default defaulted tuples - we are going to a
-                    // different infcx, and the default will just cause
-                    // pollution.
-                    self.tcx().intern_tup(tys, false)
-                }
                 _ => {
                     t.super_fold_with(self)
                 }
diff --git a/src/librustc/lint/builtin.rs b/src/librustc/lint/builtin.rs
index 8e1f76c501800..1795866e103b3 100644
--- a/src/librustc/lint/builtin.rs
+++ b/src/librustc/lint/builtin.rs
@@ -151,13 +151,6 @@ declare_lint! {
     "lints that have been renamed or removed"
 }
 
-declare_lint! {
-    pub RESOLVE_TRAIT_ON_DEFAULTED_UNIT,
-    Deny,
-    "attempt to resolve a trait on an expression whose type cannot be inferred but which \
-     currently defaults to ()"
-}
-
 declare_lint! {
     pub SAFE_EXTERN_STATICS,
     Deny,
@@ -304,7 +297,6 @@ impl LintPass for HardwiredLints {
             INVALID_TYPE_PARAM_DEFAULT,
             CONST_ERR,
             RENAMED_AND_REMOVED_LINTS,
-            RESOLVE_TRAIT_ON_DEFAULTED_UNIT,
             SAFE_EXTERN_STATICS,
             SAFE_PACKED_BORROWS,
             PATTERNS_IN_FNS_WITHOUT_BODY,
diff --git a/src/librustc/middle/mem_categorization.rs b/src/librustc/middle/mem_categorization.rs
index 30d63b8443e3d..6bf0c5d1ba3e3 100644
--- a/src/librustc/middle/mem_categorization.rs
+++ b/src/librustc/middle/mem_categorization.rs
@@ -1298,7 +1298,7 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
           PatKind::Tuple(ref subpats, ddpos) => {
             // (p1, ..., pN)
             let expected_len = match self.pat_ty(&pat)?.sty {
-                ty::TyTuple(ref tys, _) => tys.len(),
+                ty::TyTuple(ref tys) => tys.len(),
                 ref ty => span_bug!(pat.span, "tuple pattern unexpected type {:?}", ty),
             };
             for (i, subpat) in subpats.iter().enumerate_and_adjust(expected_len, ddpos) {
diff --git a/src/librustc/mir/tcx.rs b/src/librustc/mir/tcx.rs
index d779ccd17360a..20902d9111019 100644
--- a/src/librustc/mir/tcx.rs
+++ b/src/librustc/mir/tcx.rs
@@ -155,7 +155,7 @@ impl<'tcx> Rvalue<'tcx> {
                 let lhs_ty = lhs.ty(local_decls, tcx);
                 let rhs_ty = rhs.ty(local_decls, tcx);
                 let ty = op.ty(tcx, lhs_ty, rhs_ty);
-                tcx.intern_tup(&[ty, tcx.types.bool], false)
+                tcx.intern_tup(&[ty, tcx.types.bool])
             }
             Rvalue::UnaryOp(UnOp::Not, ref operand) |
             Rvalue::UnaryOp(UnOp::Neg, ref operand) => {
@@ -178,10 +178,7 @@ impl<'tcx> Rvalue<'tcx> {
                         tcx.mk_array(ty, ops.len() as u64)
                     }
                     AggregateKind::Tuple => {
-                        tcx.mk_tup(
-                            ops.iter().map(|op| op.ty(local_decls, tcx)),
-                            false
-                        )
+                        tcx.mk_tup(ops.iter().map(|op| op.ty(local_decls, tcx)))
                     }
                     AggregateKind::Adt(def, _, substs, _) => {
                         tcx.type_of(def.did).subst(tcx, substs)
diff --git a/src/librustc/traits/error_reporting.rs b/src/librustc/traits/error_reporting.rs
index b8455b97fa41f..5d994a0e444c6 100644
--- a/src/librustc/traits/error_reporting.rs
+++ b/src/librustc/traits/error_reporting.rs
@@ -729,14 +729,14 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                 }).map(|sp| self.tcx.sess.codemap().def_span(sp)); // the sp could be an fn def
 
                 let found = match found_trait_ref.skip_binder().substs.type_at(1).sty {
-                    ty::TyTuple(ref tys, _) => tys.iter()
+                    ty::TyTuple(ref tys) => tys.iter()
                         .map(|_| ArgKind::empty()).collect::<Vec<_>>(),
                     _ => vec![ArgKind::empty()],
                 };
                 let expected = match expected_trait_ref.skip_binder().substs.type_at(1).sty {
-                    ty::TyTuple(ref tys, _) => tys.iter()
+                    ty::TyTuple(ref tys) => tys.iter()
                         .map(|t| match t.sty {
-                            ty::TypeVariants::TyTuple(ref tys, _) => ArgKind::Tuple(
+                            ty::TypeVariants::TyTuple(ref tys) => ArgKind::Tuple(
                                 Some(span),
                                 tys.iter()
                                     .map(|ty| ("_".to_owned(), format!("{}", ty.sty)))
@@ -986,7 +986,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         fn build_fn_sig_string<'a, 'gcx, 'tcx>(tcx: ty::TyCtxt<'a, 'gcx, 'tcx>,
                                                trait_ref: &ty::TraitRef<'tcx>) -> String {
             let inputs = trait_ref.substs.type_at(1);
-            let sig = if let ty::TyTuple(inputs, _) = inputs.sty {
+            let sig = if let ty::TyTuple(inputs) = inputs.sty {
                 tcx.mk_fn_sig(
                     inputs.iter().map(|&x| x),
                     tcx.mk_infer(ty::TyVar(ty::TyVid { index: 0 })),
@@ -1422,7 +1422,7 @@ impl ArgKind {
     /// argument. This has no name (`_`) and no source spans..
     pub fn from_expected_ty(t: Ty<'_>) -> ArgKind {
         match t.sty {
-            ty::TyTuple(ref tys, _) => ArgKind::Tuple(
+            ty::TyTuple(ref tys) => ArgKind::Tuple(
                 None,
                 tys.iter()
                    .map(|ty| ("_".to_owned(), format!("{}", ty.sty)))
diff --git a/src/librustc/traits/fulfill.rs b/src/librustc/traits/fulfill.rs
index bb2c7977f265b..150a2ead9e96d 100644
--- a/src/librustc/traits/fulfill.rs
+++ b/src/librustc/traits/fulfill.rs
@@ -330,11 +330,7 @@ fn process_predicate<'a, 'gcx, 'tcx>(
             if data.is_global() {
                 // no type variables present, can use evaluation for better caching.
                 // FIXME: consider caching errors too.
-                if
-                    // make defaulted unit go through the slow path for better warnings,
-                    // please remove this when the warnings are removed.
-                    !trait_obligation.predicate.skip_binder().self_ty().is_defaulted_unit() &&
-                    selcx.evaluate_obligation_conservatively(&obligation) {
+                if selcx.evaluate_obligation_conservatively(&obligation) {
                     debug!("selecting trait `{:?}` at depth {} evaluated to holds",
                            data, obligation.recursion_depth);
                     return Ok(Some(vec![]))
diff --git a/src/librustc/traits/select.rs b/src/librustc/traits/select.rs
index f2f54dcedfd65..4db81cf1dec1d 100644
--- a/src/librustc/traits/select.rs
+++ b/src/librustc/traits/select.rs
@@ -53,7 +53,6 @@ use std::mem;
 use std::rc::Rc;
 use syntax::abi::Abi;
 use hir;
-use lint;
 use util::nodemap::{FxHashMap, FxHashSet};
 
 
@@ -526,54 +525,12 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
         debug!("select({:?})", obligation);
         assert!(!obligation.predicate.has_escaping_regions());
 
-        let tcx = self.tcx();
-
         let stack = self.push_stack(TraitObligationStackList::empty(), obligation);
         let ret = match self.candidate_from_obligation(&stack)? {
             None => None,
             Some(candidate) => Some(self.confirm_candidate(obligation, candidate)?)
         };
 
-        // Test whether this is a `()` which was produced by defaulting a
-        // diverging type variable with `!` disabled. If so, we may need
-        // to raise a warning.
-        if obligation.predicate.skip_binder().self_ty().is_defaulted_unit() {
-            let mut raise_warning = true;
-            // Don't raise a warning if the trait is implemented for ! and only
-            // permits a trivial implementation for !. This stops us warning
-            // about (for example) `(): Clone` becoming `!: Clone` because such
-            // a switch can't cause code to stop compiling or execute
-            // differently.
-            let mut never_obligation = obligation.clone();
-            let def_id = never_obligation.predicate.skip_binder().trait_ref.def_id;
-            never_obligation.predicate = never_obligation.predicate.map_bound(|mut trait_pred| {
-                // Swap out () with ! so we can check if the trait is impld for !
-                {
-                    let trait_ref = &mut trait_pred.trait_ref;
-                    let unit_substs = trait_ref.substs;
-                    let mut never_substs = Vec::with_capacity(unit_substs.len());
-                    never_substs.push(tcx.types.never.into());
-                    never_substs.extend(&unit_substs[1..]);
-                    trait_ref.substs = tcx.intern_substs(&never_substs);
-                }
-                trait_pred
-            });
-            if let Ok(Some(..)) = self.select(&never_obligation) {
-                if !tcx.trait_relevant_for_never(def_id) {
-                    // The trait is also implemented for ! and the resulting
-                    // implementation cannot actually be invoked in any way.
-                    raise_warning = false;
-                }
-            }
-
-            if raise_warning {
-                tcx.lint_node(lint::builtin::RESOLVE_TRAIT_ON_DEFAULTED_UNIT,
-                              obligation.cause.body_id,
-                              obligation.cause.span,
-                              &format!("code relies on type inference rules which are likely \
-                                        to change"));
-            }
-        }
         Ok(ret)
     }
 
@@ -1929,7 +1886,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
             }
 
             // (.., T) -> (.., U).
-            (&ty::TyTuple(tys_a, _), &ty::TyTuple(tys_b, _)) => {
+            (&ty::TyTuple(tys_a), &ty::TyTuple(tys_b)) => {
                 tys_a.len() == tys_b.len()
             }
 
@@ -2068,7 +2025,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
 
             ty::TyStr | ty::TySlice(_) | ty::TyDynamic(..) | ty::TyForeign(..) => Never,
 
-            ty::TyTuple(tys, _) => {
+            ty::TyTuple(tys) => {
                 Where(ty::Binder(tys.last().into_iter().cloned().collect()))
             }
 
@@ -2122,7 +2079,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
                 Where(ty::Binder(vec![element_ty]))
             }
 
-            ty::TyTuple(tys, _) => {
+            ty::TyTuple(tys) => {
                 // (*) binder moved here
                 Where(ty::Binder(tys.to_vec()))
             }
@@ -2215,7 +2172,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
                 vec![element_ty]
             }
 
-            ty::TyTuple(ref tys, _) => {
+            ty::TyTuple(ref tys) => {
                 // (T1, ..., Tn) -- meets any bound that all of T1...Tn meet
                 tys.to_vec()
             }
@@ -3004,7 +2961,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
             }
 
             // (.., T) -> (.., U).
-            (&ty::TyTuple(tys_a, _), &ty::TyTuple(tys_b, _)) => {
+            (&ty::TyTuple(tys_a), &ty::TyTuple(tys_b)) => {
                 assert_eq!(tys_a.len(), tys_b.len());
 
                 // The last field of the tuple has to exist.
@@ -3017,7 +2974,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
 
                 // Check that the source tuple with the target's
                 // last element is equal to the target.
-                let new_tuple = tcx.mk_tup(a_mid.iter().chain(Some(b_last)), false);
+                let new_tuple = tcx.mk_tup(a_mid.iter().chain(Some(b_last)));
                 let InferOk { obligations, .. } =
                     self.infcx.at(&obligation.cause, obligation.param_env)
                               .eq(target, new_tuple)
diff --git a/src/librustc/traits/util.rs b/src/librustc/traits/util.rs
index c562f2cd48dde..8f7a24057472c 100644
--- a/src/librustc/traits/util.rs
+++ b/src/librustc/traits/util.rs
@@ -503,7 +503,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         let arguments_tuple = match tuple_arguments {
             TupleArgumentsFlag::No => sig.skip_binder().inputs()[0],
             TupleArgumentsFlag::Yes =>
-                self.intern_tup(sig.skip_binder().inputs(), false),
+                self.intern_tup(sig.skip_binder().inputs()),
         };
         let trait_ref = ty::TraitRef {
             def_id: fn_trait_def_id,
diff --git a/src/librustc/ty/context.rs b/src/librustc/ty/context.rs
index 9a687028b582c..fd3465f59ebf2 100644
--- a/src/librustc/ty/context.rs
+++ b/src/librustc/ty/context.rs
@@ -2014,7 +2014,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
     pub fn coerce_closure_fn_ty(self, sig: PolyFnSig<'tcx>) -> Ty<'tcx> {
         let converted_sig = sig.map_bound(|s| {
             let params_iter = match s.inputs()[0].sty {
-                ty::TyTuple(params, _) => {
+                ty::TyTuple(params) => {
                     params.into_iter().cloned()
                 }
                 _ => bug!(),
@@ -2134,25 +2134,16 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         self.mk_ty(TySlice(ty))
     }
 
-    pub fn intern_tup(self, ts: &[Ty<'tcx>], defaulted: bool) -> Ty<'tcx> {
-        self.mk_ty(TyTuple(self.intern_type_list(ts), defaulted))
+    pub fn intern_tup(self, ts: &[Ty<'tcx>]) -> Ty<'tcx> {
+        self.mk_ty(TyTuple(self.intern_type_list(ts)))
     }
 
-    pub fn mk_tup<I: InternAs<[Ty<'tcx>], Ty<'tcx>>>(self, iter: I,
-                                                     defaulted: bool) -> I::Output {
-        iter.intern_with(|ts| self.mk_ty(TyTuple(self.intern_type_list(ts), defaulted)))
+    pub fn mk_tup<I: InternAs<[Ty<'tcx>], Ty<'tcx>>>(self, iter: I) -> I::Output {
+        iter.intern_with(|ts| self.mk_ty(TyTuple(self.intern_type_list(ts))))
     }
 
     pub fn mk_nil(self) -> Ty<'tcx> {
-        self.intern_tup(&[], false)
-    }
-
-    pub fn mk_diverging_default(self) -> Ty<'tcx> {
-        if self.features().never_type {
-            self.types.never
-        } else {
-            self.intern_tup(&[], true)
-        }
+        self.intern_tup(&[])
     }
 
     pub fn mk_bool(self) -> Ty<'tcx> {
diff --git a/src/librustc/ty/error.rs b/src/librustc/ty/error.rs
index 8a0253ed2f115..eb3924186472c 100644
--- a/src/librustc/ty/error.rs
+++ b/src/librustc/ty/error.rs
@@ -177,7 +177,7 @@ impl<'a, 'gcx, 'lcx, 'tcx> ty::TyS<'tcx> {
         match self.sty {
             ty::TyBool | ty::TyChar | ty::TyInt(_) |
             ty::TyUint(_) | ty::TyFloat(_) | ty::TyStr | ty::TyNever => self.to_string(),
-            ty::TyTuple(ref tys, _) if tys.is_empty() => self.to_string(),
+            ty::TyTuple(ref tys) if tys.is_empty() => self.to_string(),
 
             ty::TyAdt(def, _) => format!("{} `{}`", def.descr(), tcx.item_path_str(def.did)),
             ty::TyForeign(def_id) => format!("extern type `{}`", tcx.item_path_str(def_id)),
diff --git a/src/librustc/ty/fast_reject.rs b/src/librustc/ty/fast_reject.rs
index 93d8a4d979de6..6533a7440ac38 100644
--- a/src/librustc/ty/fast_reject.rs
+++ b/src/librustc/ty/fast_reject.rs
@@ -97,7 +97,7 @@ pub fn simplify_type<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
             Some(GeneratorWitnessSimplifiedType(tys.skip_binder().len()))
         }
         ty::TyNever => Some(NeverSimplifiedType),
-        ty::TyTuple(ref tys, _) => {
+        ty::TyTuple(ref tys) => {
             Some(TupleSimplifiedType(tys.len()))
         }
         ty::TyFnPtr(ref f) => {
diff --git a/src/librustc/ty/flags.rs b/src/librustc/ty/flags.rs
index cae64fd4c95c6..086fc66c70f9d 100644
--- a/src/librustc/ty/flags.rs
+++ b/src/librustc/ty/flags.rs
@@ -179,10 +179,7 @@ impl FlagComputation {
                 self.add_ty(m.ty);
             }
 
-            &ty::TyTuple(ref ts, is_default) => {
-                if is_default {
-                    self.add_flags(TypeFlags::KEEP_IN_LOCAL_TCX);
-                }
+            &ty::TyTuple(ref ts) => {
                 self.add_tys(&ts[..]);
             }
 
diff --git a/src/librustc/ty/inhabitedness/mod.rs b/src/librustc/ty/inhabitedness/mod.rs
index 3e653cf126a8d..325f8575fd0a7 100644
--- a/src/librustc/ty/inhabitedness/mod.rs
+++ b/src/librustc/ty/inhabitedness/mod.rs
@@ -256,7 +256,7 @@ impl<'a, 'gcx, 'tcx> TyS<'tcx> {
             },
 
             TyNever => DefIdForest::full(tcx),
-            TyTuple(ref tys, _) => {
+            TyTuple(ref tys) => {
                 DefIdForest::union(tcx, tys.iter().map(|ty| {
                     ty.uninhabited_from(visited, tcx)
                 }))
diff --git a/src/librustc/ty/item_path.rs b/src/librustc/ty/item_path.rs
index fefd11eecf4fa..1f23b0a27e33d 100644
--- a/src/librustc/ty/item_path.rs
+++ b/src/librustc/ty/item_path.rs
@@ -355,9 +355,9 @@ pub fn characteristic_def_id_of_type(ty: Ty) -> Option<DefId> {
         ty::TyRawPtr(mt) |
         ty::TyRef(_, mt) => characteristic_def_id_of_type(mt.ty),
 
-        ty::TyTuple(ref tys, _) => tys.iter()
-                                      .filter_map(|ty| characteristic_def_id_of_type(ty))
-                                      .next(),
+        ty::TyTuple(ref tys) => tys.iter()
+                                   .filter_map(|ty| characteristic_def_id_of_type(ty))
+                                   .next(),
 
         ty::TyFnDef(def_id, _) |
         ty::TyClosure(def_id, _) |
diff --git a/src/librustc/ty/layout.rs b/src/librustc/ty/layout.rs
index 04353d2ece192..3a3f10cb87db4 100644
--- a/src/librustc/ty/layout.rs
+++ b/src/librustc/ty/layout.rs
@@ -1318,7 +1318,7 @@ impl<'a, 'tcx> LayoutCx<'tcx, TyCtxt<'a, 'tcx, 'tcx>> {
                     StructKind::AlwaysSized)?
             }
 
-            ty::TyTuple(tys, _) => {
+            ty::TyTuple(tys) => {
                 let kind = if tys.len() == 0 {
                     StructKind::AlwaysSized
                 } else {
@@ -2243,7 +2243,7 @@ impl<'a, 'tcx> TyLayout<'tcx> {
                 substs.field_tys(def_id, tcx).nth(i).unwrap()
             }
 
-            ty::TyTuple(tys, _) => tys[i],
+            ty::TyTuple(tys) => tys[i],
 
             // SIMD vector types.
             ty::TyAdt(def, ..) if def.repr.simd() => {
diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
index fc1d26b0e0910..09b11a36352e1 100644
--- a/src/librustc/ty/mod.rs
+++ b/src/librustc/ty/mod.rs
@@ -2046,7 +2046,7 @@ impl<'a, 'gcx, 'tcx> AdtDef {
                 vec![ty]
             }
 
-            TyTuple(ref tys, _) => {
+            TyTuple(ref tys) => {
                 match tys.last() {
                     None => vec![],
                     Some(ty) => self.sized_constraint_for_ty(tcx, ty)
diff --git a/src/librustc/ty/relate.rs b/src/librustc/ty/relate.rs
index 72e7d16b64dce..36eb3e3f94cfa 100644
--- a/src/librustc/ty/relate.rs
+++ b/src/librustc/ty/relate.rs
@@ -529,11 +529,10 @@ pub fn super_relate_tys<'a, 'gcx, 'tcx, R>(relation: &mut R,
             Ok(tcx.mk_slice(t))
         }
 
-        (&ty::TyTuple(as_, a_defaulted), &ty::TyTuple(bs, b_defaulted)) =>
+        (&ty::TyTuple(as_), &ty::TyTuple(bs)) =>
         {
             if as_.len() == bs.len() {
-                let defaulted = a_defaulted || b_defaulted;
-                Ok(tcx.mk_tup(as_.iter().zip(bs).map(|(a, b)| relation.relate(a, b)), defaulted)?)
+                Ok(tcx.mk_tup(as_.iter().zip(bs).map(|(a, b)| relation.relate(a, b)))?)
             } else if !(as_.is_empty() || bs.is_empty()) {
                 Err(TypeError::TupleSize(
                     expected_found(relation, &as_.len(), &bs.len())))
diff --git a/src/librustc/ty/structural_impls.rs b/src/librustc/ty/structural_impls.rs
index 0627bcdfb0ec1..c9a69d5405c9a 100644
--- a/src/librustc/ty/structural_impls.rs
+++ b/src/librustc/ty/structural_impls.rs
@@ -869,7 +869,7 @@ impl<'tcx> TypeFoldable<'tcx> for Ty<'tcx> {
             ty::TyAdt(tid, substs) => ty::TyAdt(tid, substs.fold_with(folder)),
             ty::TyDynamic(ref trait_ty, ref region) =>
                 ty::TyDynamic(trait_ty.fold_with(folder), region.fold_with(folder)),
-            ty::TyTuple(ts, defaulted) => ty::TyTuple(ts.fold_with(folder), defaulted),
+            ty::TyTuple(ts) => ty::TyTuple(ts.fold_with(folder)),
             ty::TyFnDef(def_id, substs) => {
                 ty::TyFnDef(def_id, substs.fold_with(folder))
             }
@@ -908,7 +908,7 @@ impl<'tcx> TypeFoldable<'tcx> for Ty<'tcx> {
             ty::TyAdt(_, substs) => substs.visit_with(visitor),
             ty::TyDynamic(ref trait_ty, ref reg) =>
                 trait_ty.visit_with(visitor) || reg.visit_with(visitor),
-            ty::TyTuple(ts, _) => ts.visit_with(visitor),
+            ty::TyTuple(ts) => ts.visit_with(visitor),
             ty::TyFnDef(_, substs) => substs.visit_with(visitor),
             ty::TyFnPtr(ref f) => f.visit_with(visitor),
             ty::TyRef(r, ref tm) => r.visit_with(visitor) || tm.visit_with(visitor),
diff --git a/src/librustc/ty/sty.rs b/src/librustc/ty/sty.rs
index 109422564c84d..ae053d7f4f58d 100644
--- a/src/librustc/ty/sty.rs
+++ b/src/librustc/ty/sty.rs
@@ -148,11 +148,7 @@ pub enum TypeVariants<'tcx> {
     TyNever,
 
     /// A tuple type.  For example, `(i32, bool)`.
-    /// The bool indicates whether this is a unit tuple and was created by
-    /// defaulting a diverging type variable with feature(never_type) disabled.
-    /// It's only purpose is for raising future-compatibility warnings for when
-    /// diverging type variables start defaulting to ! instead of ().
-    TyTuple(&'tcx Slice<Ty<'tcx>>, bool),
+    TyTuple(&'tcx Slice<Ty<'tcx>>),
 
     /// The projection of an associated type.  For example,
     /// `<T as Trait<..>>::N`.
@@ -1274,7 +1270,7 @@ impl RegionKind {
 impl<'a, 'gcx, 'tcx> TyS<'tcx> {
     pub fn is_nil(&self) -> bool {
         match self.sty {
-            TyTuple(ref tys, _) => tys.is_empty(),
+            TyTuple(ref tys) => tys.is_empty(),
             _ => false,
         }
     }
@@ -1286,15 +1282,6 @@ impl<'a, 'gcx, 'tcx> TyS<'tcx> {
         }
     }
 
-    /// Test whether this is a `()` which was produced by defaulting a
-    /// diverging type variable with feature(never_type) disabled.
-    pub fn is_defaulted_unit(&self) -> bool {
-        match self.sty {
-            TyTuple(_, true) => true,
-            _ => false,
-        }
-    }
-
     pub fn is_primitive(&self) -> bool {
         match self.sty {
             TyBool | TyChar | TyInt(_) | TyUint(_) | TyFloat(_) => true,
diff --git a/src/librustc/ty/util.rs b/src/librustc/ty/util.rs
index 753f89d8cd293..91d460a96f785 100644
--- a/src/librustc/ty/util.rs
+++ b/src/librustc/ty/util.rs
@@ -269,7 +269,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                 // Don't use `non_enum_variant`, this may be a univariant enum.
                 adt.variants[0].fields.get(i).map(|f| f.ty(self, substs))
             }
-            (&TyTuple(ref v, _), None) => v.get(i).cloned(),
+            (&TyTuple(ref v), None) => v.get(i).cloned(),
             _ => None,
         }
     }
@@ -307,7 +307,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                     }
                 }
 
-                ty::TyTuple(tys, _) => {
+                ty::TyTuple(tys) => {
                     if let Some((&last_ty, _)) = tys.split_last() {
                         ty = last_ty;
                     } else {
@@ -344,7 +344,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                         break;
                     }
                 },
-                (&TyTuple(a_tys, _), &TyTuple(b_tys, _))
+                (&TyTuple(a_tys), &TyTuple(b_tys))
                         if a_tys.len() == b_tys.len() => {
                     if let Some(a_last) = a_tys.last() {
                         a = a_last;
@@ -709,9 +709,8 @@ impl<'a, 'gcx, 'tcx, W> TypeVisitor<'tcx> for TypeIdHasher<'a, 'gcx, 'tcx, W>
             TyGeneratorWitness(tys) => {
                 self.hash(tys.skip_binder().len());
             }
-            TyTuple(tys, defaulted) => {
+            TyTuple(tys) => {
                 self.hash(tys.len());
-                self.hash(defaulted);
             }
             TyParam(p) => {
                 self.hash(p.idx);
@@ -838,7 +837,7 @@ impl<'a, 'tcx> ty::TyS<'tcx> {
             -> Representability
         {
             match ty.sty {
-                TyTuple(ref ts, _) => {
+                TyTuple(ref ts) => {
                     // Find non representable
                     fold_repr(ts.iter().map(|ty| {
                         is_type_structurally_recursive(tcx, sp, seen, representable_cache, ty)
@@ -1106,7 +1105,7 @@ fn needs_drop_raw<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         // state transformation pass
         ty::TyGenerator(..) => true,
 
-        ty::TyTuple(ref tys, _) => tys.iter().cloned().any(needs_drop),
+        ty::TyTuple(ref tys) => tys.iter().cloned().any(needs_drop),
 
         // unions don't have destructors regardless of the child types
         ty::TyAdt(def, _) if def.is_union() => false,
diff --git a/src/librustc/ty/walk.rs b/src/librustc/ty/walk.rs
index 722fdfe773a98..46c048e839b4b 100644
--- a/src/librustc/ty/walk.rs
+++ b/src/librustc/ty/walk.rs
@@ -125,7 +125,7 @@ fn push_subtypes<'tcx>(stack: &mut TypeWalkerStack<'tcx>, parent_ty: Ty<'tcx>) {
         ty::TyGeneratorWitness(ts) => {
             stack.extend(ts.skip_binder().iter().cloned().rev());
         }
-        ty::TyTuple(ts, _) => {
+        ty::TyTuple(ts) => {
             stack.extend(ts.iter().cloned().rev());
         }
         ty::TyFnDef(_, substs) => {
diff --git a/src/librustc/ty/wf.rs b/src/librustc/ty/wf.rs
index 49ae79ae9c92c..f05d56c9d8371 100644
--- a/src/librustc/ty/wf.rs
+++ b/src/librustc/ty/wf.rs
@@ -275,7 +275,7 @@ impl<'a, 'gcx, 'tcx> WfPredicates<'a, 'gcx, 'tcx> {
                     self.compute_const(len);
                 }
 
-                ty::TyTuple(ref tys, _) => {
+                ty::TyTuple(ref tys) => {
                     if let Some((_last, rest)) = tys.split_last() {
                         for elem in rest {
                             self.require_sized(elem, traits::TupleElem);
diff --git a/src/librustc/util/ppaux.rs b/src/librustc/util/ppaux.rs
index efa53c775ae25..2c3ee1ec285a9 100644
--- a/src/librustc/util/ppaux.rs
+++ b/src/librustc/util/ppaux.rs
@@ -340,7 +340,7 @@ impl PrintContext {
 
         if !verbose && fn_trait_kind.is_some() && projections.len() == 1 {
             let projection_ty = projections[0].ty;
-            if let TyTuple(ref args, _) = substs.type_at(1).sty {
+            if let TyTuple(ref args) = substs.type_at(1).sty {
                 return self.fn_sig(f, args, false, projection_ty);
             }
         }
@@ -1013,7 +1013,7 @@ define_print! {
                     tm.print(f, cx)
                 }
                 TyNever => write!(f, "!"),
-                TyTuple(ref tys, _) => {
+                TyTuple(ref tys) => {
                     write!(f, "(")?;
                     let mut tys = tys.iter();
                     if let Some(&ty) = tys.next() {
diff --git a/src/librustc_driver/test.rs b/src/librustc_driver/test.rs
index 06610609ebdbd..f7cd1c99a79dd 100644
--- a/src/librustc_driver/test.rs
+++ b/src/librustc_driver/test.rs
@@ -287,7 +287,7 @@ impl<'a, 'gcx, 'tcx> Env<'a, 'gcx, 'tcx> {
     }
 
     pub fn t_pair(&self, ty1: Ty<'tcx>, ty2: Ty<'tcx>) -> Ty<'tcx> {
-        self.infcx.tcx.intern_tup(&[ty1, ty2], false)
+        self.infcx.tcx.intern_tup(&[ty1, ty2])
     }
 
     pub fn t_param(&self, index: u32) -> Ty<'tcx> {
@@ -593,8 +593,8 @@ fn walk_ty() {
         let tcx = env.infcx.tcx;
         let int_ty = tcx.types.isize;
         let usize_ty = tcx.types.usize;
-        let tup1_ty = tcx.intern_tup(&[int_ty, usize_ty, int_ty, usize_ty], false);
-        let tup2_ty = tcx.intern_tup(&[tup1_ty, tup1_ty, usize_ty], false);
+        let tup1_ty = tcx.intern_tup(&[int_ty, usize_ty, int_ty, usize_ty]);
+        let tup2_ty = tcx.intern_tup(&[tup1_ty, tup1_ty, usize_ty]);
         let walked: Vec<_> = tup2_ty.walk().collect();
         assert_eq!(walked,
                    [tup2_ty, tup1_ty, int_ty, usize_ty, int_ty, usize_ty, tup1_ty, int_ty,
@@ -608,8 +608,8 @@ fn walk_ty_skip_subtree() {
         let tcx = env.infcx.tcx;
         let int_ty = tcx.types.isize;
         let usize_ty = tcx.types.usize;
-        let tup1_ty = tcx.intern_tup(&[int_ty, usize_ty, int_ty, usize_ty], false);
-        let tup2_ty = tcx.intern_tup(&[tup1_ty, tup1_ty, usize_ty], false);
+        let tup1_ty = tcx.intern_tup(&[int_ty, usize_ty, int_ty, usize_ty]);
+        let tup2_ty = tcx.intern_tup(&[tup1_ty, tup1_ty, usize_ty]);
 
         // types we expect to see (in order), plus a boolean saying
         // whether to skip the subtree.
diff --git a/src/librustc_lint/lib.rs b/src/librustc_lint/lib.rs
index 779aa3a9037ca..235d733b253a2 100644
--- a/src/librustc_lint/lib.rs
+++ b/src/librustc_lint/lib.rs
@@ -234,11 +234,6 @@ pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) {
             reference: "issue #39207 <https://github.com/rust-lang/rust/issues/39207>",
             epoch: None,
         },
-        FutureIncompatibleInfo {
-            id: LintId::of(RESOLVE_TRAIT_ON_DEFAULTED_UNIT),
-            reference: "issue #39216 <https://github.com/rust-lang/rust/issues/39216>",
-            epoch: None,
-        },
         FutureIncompatibleInfo {
             id: LintId::of(MISSING_FRAGMENT_SPECIFIER),
             reference: "issue #40107 <https://github.com/rust-lang/rust/issues/40107>",
diff --git a/src/librustc_lint/unused.rs b/src/librustc_lint/unused.rs
index 6ab3172c4fefa..d777f6f19b0ff 100644
--- a/src/librustc_lint/unused.rs
+++ b/src/librustc_lint/unused.rs
@@ -58,7 +58,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
 
         let t = cx.tables.expr_ty(&expr);
         let ty_warned = match t.sty {
-            ty::TyTuple(ref tys, _) if tys.is_empty() => return,
+            ty::TyTuple(ref tys) if tys.is_empty() => return,
             ty::TyNever => return,
             ty::TyAdt(def, _) => {
                 if def.variants.is_empty() {
diff --git a/src/librustc_mir/borrow_check/error_reporting.rs b/src/librustc_mir/borrow_check/error_reporting.rs
index 84ba13674505f..56371d809b26a 100644
--- a/src/librustc_mir/borrow_check/error_reporting.rs
+++ b/src/librustc_mir/borrow_check/error_reporting.rs
@@ -789,7 +789,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
                 } else {
                     format!("{}", def.non_enum_variant().fields[field.index()].name)
                 },
-                ty::TyTuple(_, _) => format!("{}", field.index()),
+                ty::TyTuple(_) => format!("{}", field.index()),
                 ty::TyRef(_, tnm) | ty::TyRawPtr(tnm) => {
                     self.describe_field_from_ty(&tnm.ty, field)
                 }
diff --git a/src/librustc_mir/borrow_check/nll/type_check/mod.rs b/src/librustc_mir/borrow_check/nll/type_check/mod.rs
index 06e6be5cd56a3..022831b5a9259 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/mod.rs
@@ -542,7 +542,7 @@ impl<'a, 'b, 'gcx, 'tcx> TypeVerifier<'a, 'b, 'gcx, 'tcx> {
                         }),
                     };
                 }
-                ty::TyTuple(tys, _) => {
+                ty::TyTuple(tys) => {
                     return match tys.get(field.index()) {
                         Some(&ty) => Ok(ty),
                         None => Err(FieldAccessError::OutOfRange {
diff --git a/src/librustc_mir/borrow_check/nll/universal_regions.rs b/src/librustc_mir/borrow_check/nll/universal_regions.rs
index 668172749fecb..afd338581392d 100644
--- a/src/librustc_mir/borrow_check/nll/universal_regions.rs
+++ b/src/librustc_mir/borrow_check/nll/universal_regions.rs
@@ -635,7 +635,7 @@ impl<'cx, 'gcx, 'tcx> UniversalRegionsBuilder<'cx, 'gcx, 'tcx> {
                         let (&output, tuplized_inputs) = inputs_and_output.split_last().unwrap();
                         assert_eq!(tuplized_inputs.len(), 1, "multiple closure inputs");
                         let inputs = match tuplized_inputs[0].sty {
-                            ty::TyTuple(inputs, _) => inputs,
+                            ty::TyTuple(inputs) => inputs,
                             _ => bug!("closure inputs not a tuple: {:?}", tuplized_inputs[0]),
                         };
 
diff --git a/src/librustc_mir/build/expr/as_rvalue.rs b/src/librustc_mir/build/expr/as_rvalue.rs
index 1a9064aab1b2f..b7f402f61a9c1 100644
--- a/src/librustc_mir/build/expr/as_rvalue.rs
+++ b/src/librustc_mir/build/expr/as_rvalue.rs
@@ -298,7 +298,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
         let source_info = self.source_info(span);
         let bool_ty = self.hir.bool_ty();
         if self.hir.check_overflow() && op.is_checkable() && ty.is_integral() {
-            let result_tup = self.hir.tcx().intern_tup(&[ty, bool_ty], false);
+            let result_tup = self.hir.tcx().intern_tup(&[ty, bool_ty]);
             let result_value = self.temp(result_tup, span);
 
             self.cfg.push_assign(block, source_info,
diff --git a/src/librustc_mir/hair/cx/expr.rs b/src/librustc_mir/hair/cx/expr.rs
index da25969bf1177..62d1b43d62570 100644
--- a/src/librustc_mir/hair/cx/expr.rs
+++ b/src/librustc_mir/hair/cx/expr.rs
@@ -227,7 +227,7 @@ fn make_mirror_unadjusted<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
 
                 let arg_tys = args.iter().map(|e| cx.tables().expr_ty_adjusted(e));
                 let tupled_args = Expr {
-                    ty: cx.tcx.mk_tup(arg_tys, false),
+                    ty: cx.tcx.mk_tup(arg_tys),
                     temp_lifetime,
                     span: expr.span,
                     kind: ExprKind::Tuple { fields: args.iter().map(ToRef::to_ref).collect() },
diff --git a/src/librustc_mir/hair/pattern/_match.rs b/src/librustc_mir/hair/pattern/_match.rs
index a3295aac80157..58aa9b06c6425 100644
--- a/src/librustc_mir/hair/pattern/_match.rs
+++ b/src/librustc_mir/hair/pattern/_match.rs
@@ -877,7 +877,7 @@ fn pat_constructors<'tcx>(_cx: &mut MatchCheckCtxt,
 fn constructor_arity(_cx: &MatchCheckCtxt, ctor: &Constructor, ty: Ty) -> u64 {
     debug!("constructor_arity({:#?}, {:?})", ctor, ty);
     match ty.sty {
-        ty::TyTuple(ref fs, _) => fs.len() as u64,
+        ty::TyTuple(ref fs) => fs.len() as u64,
         ty::TySlice(..) | ty::TyArray(..) => match *ctor {
             Slice(length) => length,
             ConstantValue(_) => 0,
@@ -901,7 +901,7 @@ fn constructor_sub_pattern_tys<'a, 'tcx: 'a>(cx: &MatchCheckCtxt<'a, 'tcx>,
 {
     debug!("constructor_sub_pattern_tys({:#?}, {:?})", ctor, ty);
     match ty.sty {
-        ty::TyTuple(ref fs, _) => fs.into_iter().map(|t| *t).collect(),
+        ty::TyTuple(ref fs) => fs.into_iter().map(|t| *t).collect(),
         ty::TySlice(ty) | ty::TyArray(ty, _) => match *ctor {
             Slice(length) => (0..length).map(|_| ty).collect(),
             ConstantValue(_) => vec![],
diff --git a/src/librustc_mir/hair/pattern/mod.rs b/src/librustc_mir/hair/pattern/mod.rs
index 1774c95af0f05..eb87d5b044b45 100644
--- a/src/librustc_mir/hair/pattern/mod.rs
+++ b/src/librustc_mir/hair/pattern/mod.rs
@@ -449,7 +449,7 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
             PatKind::Tuple(ref subpatterns, ddpos) => {
                 let ty = self.tables.node_id_to_type(pat.hir_id);
                 match ty.sty {
-                    ty::TyTuple(ref tys, _) => {
+                    ty::TyTuple(ref tys) => {
                         let subpatterns =
                             subpatterns.iter()
                                        .enumerate_and_adjust(tys.len(), ddpos)
@@ -879,7 +879,7 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
                     subpatterns: adt_subpatterns(struct_var.fields.len(), None),
                 }
             }
-            ty::TyTuple(fields, _) => {
+            ty::TyTuple(fields) => {
                 PatternKind::Leaf {
                     subpatterns: adt_subpatterns(fields.len(), None),
                 }
diff --git a/src/librustc_mir/interpret/terminator/mod.rs b/src/librustc_mir/interpret/terminator/mod.rs
index be34b8705eb18..851fac532e366 100644
--- a/src/librustc_mir/interpret/terminator/mod.rs
+++ b/src/librustc_mir/interpret/terminator/mod.rs
@@ -234,7 +234,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M> {
                     // Second argument must be a tuple matching the argument list of sig
                     let snd_ty = real_sig.inputs_and_output[1];
                     match snd_ty.sty {
-                        ty::TyTuple(tys, _) if sig.inputs().len() == tys.len() =>
+                        ty::TyTuple(tys) if sig.inputs().len() == tys.len() =>
                             if sig.inputs().iter().zip(tys).all(|(ty, real_ty)| check_ty_compat(ty, real_ty)) {
                                 return Ok(true)
                             },
diff --git a/src/librustc_mir/monomorphize/item.rs b/src/librustc_mir/monomorphize/item.rs
index 10e2a84038de1..c2f4359c0082b 100644
--- a/src/librustc_mir/monomorphize/item.rs
+++ b/src/librustc_mir/monomorphize/item.rs
@@ -281,7 +281,7 @@ impl<'a, 'tcx> DefPathBasedNames<'a, 'tcx> {
                 self.push_def_path(adt_def.did, output);
                 self.push_type_params(substs, iter::empty(), output);
             },
-            ty::TyTuple(component_types, _) => {
+            ty::TyTuple(component_types) => {
                 output.push('(');
                 for &component_type in component_types {
                     self.push_type_name(component_type, output);
diff --git a/src/librustc_mir/shim.rs b/src/librustc_mir/shim.rs
index 62af09cc49109..6a0f42c6dbb66 100644
--- a/src/librustc_mir/shim.rs
+++ b/src/librustc_mir/shim.rs
@@ -312,7 +312,7 @@ fn build_clone_shim<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                 substs.upvar_tys(def_id, tcx)
             )
         }
-        ty::TyTuple(tys, _) => builder.tuple_like_shim(dest, src, tys.iter().cloned()),
+        ty::TyTuple(tys) => builder.tuple_like_shim(dest, src, tys.iter().cloned()),
         _ => {
             bug!("clone shim for `{:?}` which is not `Copy` and is not an aggregate", self_ty)
         }
diff --git a/src/librustc_mir/transform/inline.rs b/src/librustc_mir/transform/inline.rs
index 6380d2a5c15fe..2dd805ccf9b59 100644
--- a/src/librustc_mir/transform/inline.rs
+++ b/src/librustc_mir/transform/inline.rs
@@ -599,7 +599,7 @@ impl<'a, 'tcx> Inliner<'a, 'tcx> {
             assert!(args.next().is_none());
 
             let tuple = Place::Local(tuple);
-            let tuple_tys = if let ty::TyTuple(s, _) = tuple.ty(caller_mir, tcx).to_ty(tcx).sty {
+            let tuple_tys = if let ty::TyTuple(s) = tuple.ty(caller_mir, tcx).to_ty(tcx).sty {
                 s
             } else {
                 bug!("Closure arguments are not passed as a tuple");
diff --git a/src/librustc_mir/util/elaborate_drops.rs b/src/librustc_mir/util/elaborate_drops.rs
index 3f5208dd2d4b8..e95126c8a1a0f 100644
--- a/src/librustc_mir/util/elaborate_drops.rs
+++ b/src/librustc_mir/util/elaborate_drops.rs
@@ -788,7 +788,7 @@ impl<'l, 'b, 'tcx, D> DropCtxt<'l, 'b, 'tcx, D>
                 let tys : Vec<_> = substs.upvar_tys(def_id, self.tcx()).collect();
                 self.open_drop_for_tuple(&tys)
             }
-            ty::TyTuple(tys, _) => {
+            ty::TyTuple(tys) => {
                 self.open_drop_for_tuple(tys)
             }
             ty::TyAdt(def, _) if def.is_box() => {
diff --git a/src/librustc_trans/abi.rs b/src/librustc_trans/abi.rs
index c1dc8c6684a17..4a98fff6af76d 100644
--- a/src/librustc_trans/abi.rs
+++ b/src/librustc_trans/abi.rs
@@ -722,7 +722,7 @@ impl<'a, 'tcx> FnType<'tcx> {
             assert!(!sig.variadic && extra_args.is_empty());
 
             match sig.inputs().last().unwrap().sty {
-                ty::TyTuple(ref tupled_arguments, _) => {
+                ty::TyTuple(ref tupled_arguments) => {
                     inputs = &sig.inputs()[0..sig.inputs().len() - 1];
                     tupled_arguments
                 }
diff --git a/src/librustc_trans/debuginfo/metadata.rs b/src/librustc_trans/debuginfo/metadata.rs
index 20cc57522b5d7..f3d95cf794bab 100644
--- a/src/librustc_trans/debuginfo/metadata.rs
+++ b/src/librustc_trans/debuginfo/metadata.rs
@@ -362,7 +362,7 @@ fn subroutine_type_metadata<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
 
     // return type
     signature_metadata.push(match signature.output().sty {
-        ty::TyTuple(ref tys, _) if tys.is_empty() => ptr::null_mut(),
+        ty::TyTuple(ref tys) if tys.is_empty() => ptr::null_mut(),
         _ => type_metadata(cx, signature.output(), span)
     });
 
@@ -533,7 +533,7 @@ pub fn type_metadata<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
         ty::TyFloat(_) => {
             MetadataCreationResult::new(basic_type_metadata(cx, t), false)
         }
-        ty::TyTuple(ref elements, _) if elements.is_empty() => {
+        ty::TyTuple(ref elements) if elements.is_empty() => {
             MetadataCreationResult::new(basic_type_metadata(cx, t), false)
         }
         ty::TyArray(typ, _) |
@@ -621,7 +621,7 @@ pub fn type_metadata<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
                                     usage_site_span).finalize(cx)
             }
         },
-        ty::TyTuple(ref elements, _) => {
+        ty::TyTuple(ref elements) => {
             prepare_tuple_metadata(cx,
                                    t,
                                    &elements[..],
@@ -731,7 +731,7 @@ fn basic_type_metadata<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
 
     let (name, encoding) = match t.sty {
         ty::TyNever => ("!", DW_ATE_unsigned),
-        ty::TyTuple(ref elements, _) if elements.is_empty() =>
+        ty::TyTuple(ref elements) if elements.is_empty() =>
             ("()", DW_ATE_unsigned),
         ty::TyBool => ("bool", DW_ATE_boolean),
         ty::TyChar => ("char", DW_ATE_unsigned_char),
diff --git a/src/librustc_trans/debuginfo/mod.rs b/src/librustc_trans/debuginfo/mod.rs
index c13b91eb3b6bd..7664c88679e0e 100644
--- a/src/librustc_trans/debuginfo/mod.rs
+++ b/src/librustc_trans/debuginfo/mod.rs
@@ -312,7 +312,7 @@ pub fn create_function_debug_context<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
 
         // Return type -- llvm::DIBuilder wants this at index 0
         signature.push(match sig.output().sty {
-            ty::TyTuple(ref tys, _) if tys.is_empty() => ptr::null_mut(),
+            ty::TyTuple(ref tys) if tys.is_empty() => ptr::null_mut(),
             _ => type_metadata(cx, sig.output(), syntax_pos::DUMMY_SP)
         });
 
@@ -351,7 +351,7 @@ pub fn create_function_debug_context<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
         }
 
         if sig.abi == Abi::RustCall && !sig.inputs().is_empty() {
-            if let ty::TyTuple(args, _) = sig.inputs()[sig.inputs().len() - 1].sty {
+            if let ty::TyTuple(args) = sig.inputs()[sig.inputs().len() - 1].sty {
                 for &argument_type in args {
                     signature.push(type_metadata(cx, argument_type, syntax_pos::DUMMY_SP));
                 }
diff --git a/src/librustc_trans/debuginfo/type_names.rs b/src/librustc_trans/debuginfo/type_names.rs
index 211de95c96ede..96ed4e8847115 100644
--- a/src/librustc_trans/debuginfo/type_names.rs
+++ b/src/librustc_trans/debuginfo/type_names.rs
@@ -53,7 +53,7 @@ pub fn push_debuginfo_type_name<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
             push_item_name(cx, def.did, qualified, output);
             push_type_params(cx, substs, output);
         },
-        ty::TyTuple(component_types, _) => {
+        ty::TyTuple(component_types) => {
             output.push('(');
             for &component_type in component_types {
                 push_debuginfo_type_name(cx, component_type, true, output);
diff --git a/src/librustc_trans/mir/block.rs b/src/librustc_trans/mir/block.rs
index 96c5bb3b91d2e..93bc89f0914f5 100644
--- a/src/librustc_trans/mir/block.rs
+++ b/src/librustc_trans/mir/block.rs
@@ -710,7 +710,7 @@ impl<'a, 'tcx> FunctionCx<'a, 'tcx> {
             let layout = cx.layout_of(cx.tcx.intern_tup(&[
                 cx.tcx.mk_mut_ptr(cx.tcx.types.u8),
                 cx.tcx.types.i32
-            ], false));
+            ]));
             let slot = PlaceRef::alloca(bx, layout, "personalityslot");
             self.personality_slot = Some(slot);
             slot
diff --git a/src/librustc_trans/mir/mod.rs b/src/librustc_trans/mir/mod.rs
index 0533b04a0c1d8..11dabbeae7430 100644
--- a/src/librustc_trans/mir/mod.rs
+++ b/src/librustc_trans/mir/mod.rs
@@ -448,7 +448,7 @@ fn arg_local_refs<'a, 'tcx>(bx: &Builder<'a, 'tcx>,
 
             let arg_ty = fx.monomorphize(&arg_decl.ty);
             let tupled_arg_tys = match arg_ty.sty {
-                ty::TyTuple(ref tys, _) => tys,
+                ty::TyTuple(ref tys) => tys,
                 _ => bug!("spread argument isn't a tuple?!")
             };
 
diff --git a/src/librustc_trans/mir/rvalue.rs b/src/librustc_trans/mir/rvalue.rs
index fa0514952d213..93702bfbbf3b1 100644
--- a/src/librustc_trans/mir/rvalue.rs
+++ b/src/librustc_trans/mir/rvalue.rs
@@ -399,7 +399,7 @@ impl<'a, 'tcx> FunctionCx<'a, 'tcx> {
                                                              lhs.immediate(), rhs.immediate(),
                                                              lhs.layout.ty);
                 let val_ty = op.ty(bx.tcx(), lhs.layout.ty, rhs.layout.ty);
-                let operand_ty = bx.tcx().intern_tup(&[val_ty, bx.tcx().types.bool], false);
+                let operand_ty = bx.tcx().intern_tup(&[val_ty, bx.tcx().types.bool]);
                 let operand = OperandRef {
                     val: result,
                     layout: bx.cx.layout_of(operand_ty)
diff --git a/src/librustc_typeck/astconv.rs b/src/librustc_typeck/astconv.rs
index 0df1225cf2624..827ca79334cbe 100644
--- a/src/librustc_typeck/astconv.rs
+++ b/src/librustc_typeck/astconv.rs
@@ -1050,7 +1050,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
                 tcx.types.never
             },
             hir::TyTup(ref fields) => {
-                tcx.mk_tup(fields.iter().map(|t| self.ast_ty_to_ty(&t)), false)
+                tcx.mk_tup(fields.iter().map(|t| self.ast_ty_to_ty(&t)))
             }
             hir::TyBareFn(ref bf) => {
                 require_c_abi_if_variadic(tcx, &bf.decl, bf.abi, ast_ty.span);
diff --git a/src/librustc_typeck/check/_match.rs b/src/librustc_typeck/check/_match.rs
index eb02c05fd3957..379fd93ba2bd6 100644
--- a/src/librustc_typeck/check/_match.rs
+++ b/src/librustc_typeck/check/_match.rs
@@ -319,7 +319,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 let mut expected_len = elements.len();
                 if ddpos.is_some() {
                     // Require known type only when `..` is present
-                    if let ty::TyTuple(ref tys, _) =
+                    if let ty::TyTuple(ref tys) =
                             self.structurally_resolved_type(pat.span, expected).sty {
                         expected_len = tys.len();
                     }
@@ -332,7 +332,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                     ty::UniverseIndex::ROOT,
                     TypeVariableOrigin::TypeInference(pat.span)));
                 let element_tys = tcx.mk_type_list(element_tys_iter);
-                let pat_ty = tcx.mk_ty(ty::TyTuple(element_tys, false));
+                let pat_ty = tcx.mk_ty(ty::TyTuple(element_tys));
                 self.demand_eqtype(pat.span, expected, pat_ty);
                 for (i, elem) in elements.iter().enumerate_and_adjust(max_len, ddpos) {
                     self.check_pat_walk(elem, &element_tys[i], def_bm, true);
diff --git a/src/librustc_typeck/check/cast.rs b/src/librustc_typeck/check/cast.rs
index 48bd7b14fc96a..c2c113f2da9fa 100644
--- a/src/librustc_typeck/check/cast.rs
+++ b/src/librustc_typeck/check/cast.rs
@@ -115,7 +115,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                     }
                 }
             }
-            ty::TyTuple(fields, _) => match fields.last() {
+            ty::TyTuple(fields) => match fields.last() {
                 None => Some(PointerKind::Thin),
                 Some(f) => self.pointer_kind(f, span)?
             },
diff --git a/src/librustc_typeck/check/closure.rs b/src/librustc_typeck/check/closure.rs
index 72e4b726a22b4..562c0cb1b8d0e 100644
--- a/src/librustc_typeck/check/closure.rs
+++ b/src/librustc_typeck/check/closure.rs
@@ -140,7 +140,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         // the `closures` table.
         let sig = bound_sig.map_bound(|sig| {
             self.tcx.mk_fn_sig(
-                iter::once(self.tcx.intern_tup(sig.inputs(), false)),
+                iter::once(self.tcx.intern_tup(sig.inputs())),
                 sig.output(),
                 sig.variadic,
                 sig.unsafety,
@@ -312,7 +312,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         );
 
         let input_tys = match arg_param_ty.sty {
-            ty::TyTuple(tys, _) => tys.into_iter(),
+            ty::TyTuple(tys) => tys.into_iter(),
             _ => {
                 return None;
             }
diff --git a/src/librustc_typeck/check/intrinsic.rs b/src/librustc_typeck/check/intrinsic.rs
index 2e00040d99a73..59cf8a0358efa 100644
--- a/src/librustc_typeck/check/intrinsic.rs
+++ b/src/librustc_typeck/check/intrinsic.rs
@@ -87,7 +87,7 @@ pub fn check_intrinsic_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
             "cxchg" | "cxchgweak" => (1, vec![tcx.mk_mut_ptr(param(0)),
                                               param(0),
                                               param(0)],
-                                      tcx.intern_tup(&[param(0), tcx.types.bool], false)),
+                                      tcx.intern_tup(&[param(0), tcx.types.bool])),
             "load" => (1, vec![tcx.mk_imm_ptr(param(0))],
                        param(0)),
             "store" => (1, vec![tcx.mk_mut_ptr(param(0)), param(0)],
@@ -281,7 +281,7 @@ pub fn check_intrinsic_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 
             "add_with_overflow" | "sub_with_overflow"  | "mul_with_overflow" =>
                 (1, vec![param(0), param(0)],
-                tcx.intern_tup(&[param(0), tcx.types.bool], false)),
+                tcx.intern_tup(&[param(0), tcx.types.bool])),
 
             "unchecked_div" | "unchecked_rem" =>
                 (1, vec![param(0), param(0)], param(0)),
@@ -441,7 +441,7 @@ fn match_intrinsic_type_to_type<'a, 'tcx>(
 
     match *expected {
         Void => match t.sty {
-            ty::TyTuple(ref v, _) if v.is_empty() => {},
+            ty::TyTuple(ref v) if v.is_empty() => {},
             _ => simple_error(&format!("`{}`", t), "()"),
         },
         // (The width we pass to LLVM doesn't concern the type checker.)
@@ -515,7 +515,7 @@ fn match_intrinsic_type_to_type<'a, 'tcx>(
         }
         Aggregate(_flatten, ref expected_contents) => {
             match t.sty {
-                ty::TyTuple(contents, _) => {
+                ty::TyTuple(contents) => {
                     if contents.len() != expected_contents.len() {
                         simple_error(&format!("tuple with length {}", contents.len()),
                                      &format!("tuple with length {}", expected_contents.len()));
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index 48591998a1fb8..ec6383bf9a52a 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -2160,8 +2160,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
     }
 
     // Tries to apply a fallback to `ty` if it is an unsolved variable.
-    // Non-numerics get replaced with ! or () (depending on whether
-    // feature(never_type) is enabled), unconstrained ints with i32,
+    // Non-numerics get replaced with !, unconstrained ints with i32,
     // unconstrained floats with f64.
     // Fallback becomes very dubious if we have encountered type-checking errors.
     // In that case, fallback to TyError.
@@ -2174,7 +2173,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
             _ if self.is_tainted_by_errors() => self.tcx().types.err,
             UnconstrainedInt => self.tcx.types.i32,
             UnconstrainedFloat => self.tcx.types.f64,
-            Neither if self.type_var_diverges(ty) => self.tcx.mk_diverging_default(),
+            Neither if self.type_var_diverges(ty) => self.tcx.types.never,
             Neither => return
         };
         debug!("default_type_parameters: defaulting `{:?}` to `{:?}`", ty, fallback);
@@ -2438,7 +2437,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
 
             let err_inputs = match tuple_arguments {
                 DontTupleArguments => err_inputs,
-                TupleArguments => vec![self.tcx.intern_tup(&err_inputs[..], false)],
+                TupleArguments => vec![self.tcx.intern_tup(&err_inputs[..])],
             };
 
             self.check_argument_types(sp, expr_sp, &err_inputs[..], &[], args_no_rcvr,
@@ -2531,16 +2530,16 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         let formal_tys = if tuple_arguments == TupleArguments {
             let tuple_type = self.structurally_resolved_type(sp, fn_inputs[0]);
             match tuple_type.sty {
-                ty::TyTuple(arg_types, _) if arg_types.len() != args.len() => {
+                ty::TyTuple(arg_types) if arg_types.len() != args.len() => {
                     parameter_count_error(tcx.sess, sp, expr_sp, arg_types.len(), args.len(),
                                           "E0057", false, def_span, false);
                     expected_arg_tys = &[];
                     self.err_args(args.len())
                 }
-                ty::TyTuple(arg_types, _) => {
+                ty::TyTuple(arg_types) => {
                     expected_arg_tys = match expected_arg_tys.get(0) {
                         Some(&ty) => match ty.sty {
-                            ty::TyTuple(ref tys, _) => &tys,
+                            ty::TyTuple(ref tys) => &tys,
                             _ => &[]
                         },
                         None => &[]
@@ -3193,7 +3192,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                         None
                     }
                 }
-                ty::TyTuple(ref v, _) => {
+                ty::TyTuple(ref v) => {
                     tuple_like = true;
                     v.get(idx.node).cloned()
                 }
@@ -4060,7 +4059,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
             let flds = expected.only_has_type(self).and_then(|ty| {
                 let ty = self.resolve_type_vars_with_obligations(ty);
                 match ty.sty {
-                    ty::TyTuple(ref flds, _) => Some(&flds[..]),
+                    ty::TyTuple(ref flds) => Some(&flds[..]),
                     _ => None
                 }
             });
@@ -4078,7 +4077,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 };
                 t
             });
-            let tuple = tcx.mk_tup(elt_ts_iter, false);
+            let tuple = tcx.mk_tup(elt_ts_iter);
             if tuple.references_error() {
                 tcx.types.err
             } else {
diff --git a/src/librustc_typeck/variance/constraints.rs b/src/librustc_typeck/variance/constraints.rs
index 2a4e92034de84..a24e501aba950 100644
--- a/src/librustc_typeck/variance/constraints.rs
+++ b/src/librustc_typeck/variance/constraints.rs
@@ -287,7 +287,7 @@ impl<'a, 'tcx> ConstraintContext<'a, 'tcx> {
                 self.add_constraints_from_mt(current, mt, variance);
             }
 
-            ty::TyTuple(subtys, _) => {
+            ty::TyTuple(subtys) => {
                 for &subty in subtys {
                     self.add_constraints_from_ty(current, subty, variance);
                 }
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index ff281a53ab7e4..904c24815cb7f 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -1322,7 +1322,7 @@ fn external_path_params(cx: &DocContext, trait_did: Option<DefId>, has_self: boo
         Some(did) if cx.tcx.lang_items().fn_trait_kind(did).is_some() => {
             assert_eq!(types.len(), 1);
             let inputs = match types[0].sty {
-                ty::TyTuple(ref tys, _) => tys.iter().map(|t| t.clean(cx)).collect(),
+                ty::TyTuple(ref tys) => tys.iter().map(|t| t.clean(cx)).collect(),
                 _ => {
                     return PathParameters::AngleBracketed {
                         lifetimes,
@@ -1334,7 +1334,7 @@ fn external_path_params(cx: &DocContext, trait_did: Option<DefId>, has_self: boo
             let output = None;
             // FIXME(#20299) return type comes from a projection now
             // match types[1].sty {
-            //     ty::TyTuple(ref v, _) if v.is_empty() => None, // -> ()
+            //     ty::TyTuple(ref v) if v.is_empty() => None, // -> ()
             //     _ => Some(types[1].clean(cx))
             // };
             PathParameters::Parenthesized {
@@ -1377,7 +1377,7 @@ impl<'tcx> Clean<TyParamBound> for ty::TraitRef<'tcx> {
         // collect any late bound regions
         let mut late_bounds = vec![];
         for ty_s in self.input_types().skip(1) {
-            if let ty::TyTuple(ts, _) = ty_s.sty {
+            if let ty::TyTuple(ts) = ty_s.sty {
                 for &ty_s in ts {
                     if let ty::TyRef(ref reg, _) = ty_s.sty {
                         if let &ty::RegionKind::ReLateBound(..) = *reg {
@@ -2731,7 +2731,7 @@ impl<'tcx> Clean<Type> for Ty<'tcx> {
                     Never
                 }
             }
-            ty::TyTuple(ref t, _) => Tuple(t.clean(cx)),
+            ty::TyTuple(ref t) => Tuple(t.clean(cx)),
 
             ty::TyProjection(ref data) => data.clean(cx),
 
diff --git a/src/test/compile-fail/defaulted-unit-warning.rs b/src/test/compile-fail/defaulted-unit-warning.rs
deleted file mode 100644
index 3f4e1cce548b9..0000000000000
--- a/src/test/compile-fail/defaulted-unit-warning.rs
+++ /dev/null
@@ -1,38 +0,0 @@
-// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-#![allow(unused)]
-
-trait Deserialize: Sized {
-    fn deserialize() -> Result<Self, String>;
-}
-
-impl Deserialize for () {
-    fn deserialize() -> Result<(), String> {
-        Ok(())
-    }
-}
-
-trait ImplementedForUnitButNotNever {}
-
-impl ImplementedForUnitButNotNever for () {}
-
-fn foo<T: ImplementedForUnitButNotNever>(_t: T) {}
-
-fn smeg() {
-    let _x = return;
-    foo(_x);
-    //~^ ERROR code relies on type
-    //~| WARNING previously accepted
-}
-
-fn main() {
-    smeg();
-}
diff --git a/src/test/ui/associated-types-ICE-when-projecting-out-of-err.rs b/src/test/ui/associated-types-ICE-when-projecting-out-of-err.rs
index 75b60aa8d10b7..052575de4c267 100644
--- a/src/test/ui/associated-types-ICE-when-projecting-out-of-err.rs
+++ b/src/test/ui/associated-types-ICE-when-projecting-out-of-err.rs
@@ -31,5 +31,5 @@ trait Add<RHS=Self> {
 fn ice<A>(a: A) {
     let r = loop {};
     r = r + a;
-    //~^ ERROR the trait bound `(): Add<A>` is not satisfied
+    //~^ ERROR the trait bound `!: Add<A>` is not satisfied
 }
diff --git a/src/test/ui/associated-types-ICE-when-projecting-out-of-err.stderr b/src/test/ui/associated-types-ICE-when-projecting-out-of-err.stderr
index 7924ab7444406..c22a645385ade 100644
--- a/src/test/ui/associated-types-ICE-when-projecting-out-of-err.stderr
+++ b/src/test/ui/associated-types-ICE-when-projecting-out-of-err.stderr
@@ -1,8 +1,8 @@
-error[E0277]: the trait bound `(): Add<A>` is not satisfied
+error[E0277]: the trait bound `!: Add<A>` is not satisfied
   --> $DIR/associated-types-ICE-when-projecting-out-of-err.rs:33:11
    |
 LL |     r = r + a;
-   |           ^ the trait `Add<A>` is not implemented for `()`
+   |           ^ the trait `Add<A>` is not implemented for `!`
 
 error: aborting due to previous error